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Flare-associated shock waves observed in soft X-ray

The 6 th Solar-B Science Meeting 09-Nov-2005 Kyoto, JAPAN. Flare-associated shock waves observed in soft X-ray. NARUKAGE Noriyuki Kwasan and Hida Observatories, Kyoto University – DC3. Outline. flare-associated wave propagation of shock wave Yohkoh /SXT (previous work)

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Flare-associated shock waves observed in soft X-ray

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  1. The 6thSolar-B Science Meeting 09-Nov-2005 Kyoto, JAPAN Flare-associated shock wavesobserved in soft X-ray NARUKAGE Noriyuki Kwasan and Hida Observatories,Kyoto University – DC3

  2. Outline • flare-associated wave • propagation of shock wave • Yohkoh/SXT (previous work) • Solar-B/XRT (observational plan) • counterpart of EIT waves • summary

  3. 1 flare-associated wave

  4. Flare-associated waves 1

  5. Moreton wave 1997/11/04 1 Eto et al., 2002 solar Flare Monitor Telescope (FMT)Hida Obserbatory, Kyoto Univ. The FMT observes four full disk images, in Ha (linecenter and ＋/－ 0.8 Å) and continuum, and one solar limb image in Ha center.

  6. Observable region of flare waves Moreton waves usually become visibleonly at a distance of more than100,000 km fromthe flare site. Some flare wavescan propagateup to distance exceeding 500,000 km. 1 Moreton wave & X-ray wave solar disk Observable region of flare waves flare site Propagation speed is 500 ~ 1500 km/s. (Smith and Harvey, 1971)

  7. Uchida model (1968) flare site 1 Uchida identified the Moreton wave as the intersections of a coronal MHD fast shock front and the chromosphere. shock front Moreton wave X-ray wave,coronal counterpart of Moreton wave solar disk

  8. Moreton wave and filament eruption Good correlation between the direction of wave propagation and filament eruption. 1 W j N S filament eruption W E In all Moreton wave events, filament eruptions were observed. N W W N S E W Moreton wave

  9. Global magnetic field 1 1997/11/04 • Moreton waves tend to propagate along the global magnetic fields.

  10. Double shock generation 1 High-resoluble observation of Moreton wave with Hida/SMART Solar Magnetic Activity Research Telescope (SMART)Hida Obserbatory, Kyoto Univ. The SMART is a state-of-the-art instrument that combines high resolution Ha full disk observations and vector magnetic field measurements. Our latest work of the Moreton wave

  11. Double shock generation Moreton wave ~ 950 km/s ~ 700 km/s Narukage et al., 2005 1 Moreton waves, RHESSI & type II radio burst

  12. X-ray wave 1997/11/03 1 Narukage et al., 2002 Yohkoh / SXT[Soft X-ray] Quarter resolution Half resolution Hida obs / FMT [Ha+0.8Å] Running difference

  13. Study of shock wave 1 Question • How is the shock wave generated? • key : filament eruption, magnetic field in flare region • How does the shock wave propagate? • key : global magnetic field • application : global coronal seismology • How much energy does spend on the shock generation and propagation?  The shock observation in X-ray is indispensable, because we need the physical quantities.

  14. 2 propagation of shock wave 1. Yohkoh/SXT (previous work)

  15. Advantage of Yohkoh / SXT 2.1 Using Yohkoh / SXT images, we can estimate the quantities of the X-ray wave.

  16. Is the X-ray wave a MHD fast shock? 2.1 BEHIND AHEAD Shock front IX2 T2 B2 θ2 v2 IX1 T1 B1 θ1 v1 Using MHD Eq. (1)-(7), the observable quantities (IX1,IX2,T1,B1,θ1) by Yohkoh/SXT determine (v1,T2,B2,θ2,v2).

  17. Is the X-ray wave a MHD fast shock? 2.1 Using this method, we can estimate the quantities of the X-ray wave. e.g.The estimated fast shock speed (v1) is 400 ~ 760 km/s,which is roughly agreement withthe observed propagation speed of the X-ray wave, 630 km/s. The fast mode Mach number is 1.15 ~ 1.25. These results suggest that the X-ray wave is an MHD fast shock propagating through the corona and hence is the coronal counterpart of the Moreton wave. Narukage et al. 2002, ApJ Letters 572, 109

  18. estimated Mach number 2.1 X-ray wave observed on 2000/03/03, • The fast mode Mach number decreased. • The timing when the Mach number become “1” consists with the disappearance of the Moreton wave.  We need more example! Narukage et al. 2004, PASJ, 56, L5 out of VOF ?

  19. 2 propagation of shock wave 2. Solar-B/XRT

  20. Solar-B 2.2 Using our method, we can examine the possibility of wave detection with XRT and suggest the observational plan.

  21. XRT – field of view Field of viewThe observationsof X-ray waves require the field of view as larger than 512” x 512”. 2.2 X-Ray Telescope Observable region of flare waves flare site 512” x 512” 1024” x 1024”

  22. XRT – cadence & pixel size 2.2 X-Ray Telescope • Pixel sizeThe thickness of the wave isabout 40,000 km. • Time cadenceThe propagation speeds of X-ray wave are 500 ~ 1500 km/s.  The pixel size should besmaller than 4” x 4”. • We can observe for less than 270 ~ 800 sec.The observation needs as high cadence as possible. BEHINDIx2 AHEADIx1 The FOV, pixel size and time cadence are depend on the data recorder capacity (15% of 8Gbits = 1.2Gbits = 150Mb).

  23. XRT – filter 2.2 X-Ray Telescope • Filter selectionXRT has 9 filters.We need 2 filters to estimatethe plasma temperature andemission measure.

  24. XRT – filter selection 2.2 I calculate the XRT intensities (Ix1 and Ix2)and their ratios, using my result of Yohkoh X-ray wave. To recognize the shock against the background, the intensity ratio (=Ix2 / Ix1) should be large. Bold font : A filter wheelNormal font : B filter wheel

  25. XRT – filter selection 2.2 X-Ray Telescope • I examine the enough exposure time ( t ) to suppress the effect of photon noise s. s [DN] = N1/2 [p] * 300 (conversion factor) [e-/p] / 57 [e-/ DN] (Ix2 – Ix1) t > 3s(t) Note : photon noise is superior to the other noise. • Photon noise = N1/2 * 300e- • System noise < 30e- • Dark = 0.1e- / sec / pix  I select the suitable filters for X-ray waves.

  26. XRT – observational plan 2.2 X-Ray Telescope • We suppose the shock observation mode. Following plan is a minimum-data-size plan.

  27. 3 counterpart ofEIT waves Solar-B/XRT

  28. EIT wave 3

  29. EIT wave 3 • Diffuse coronal wave – appearing as an EUV emission front (Thompson et al. 1999) • Primarily observed in EIT 195Å (1.6 MK) • Speeds ~ few hundred km/s • propagates nearly isotropically and often globally • Correlated with CME’s(Biesecker et al 2002) • Models – What is EIT wave? Big puzzle! • fast magnetoacoustic waves(Wang 2000; Warmuth et al. 2001; Ofman & Thompson 2002) • super-Alfvenic shock waves(Cameron & Uchida 2001; Khan & Aurass 2002) • field line openings (Delane´e 2000; Chen et al. 2005)

  30. EIT wave 3 Multi-wave lengthobservation ofEIT waves • 195 A – 1.5 MK • 171 A – 1.0 MK • 284 A – 0.7 MK • 304 A – 0.5 MK • SXI – open,Med Poly, Thin Be Thin Al mesh Thin Al mesh - Thin Al poly Thin Al poly XRT can observethe counterpart of EIT waves.

  31. summary 4 • Shock wave (X-ray wave) • Using Solar-B/XRT, we can estimate the physical quantities of the shock waves during the propagation. Especially, the change of the quantities is important. • Counterpart of EIT wave • XRT can observe the counterpart of the EIT waves.  I suppose the observation with “C poly(shock wave), thin Al poly(shock and EIT wave) and thin Al mesh(EIT wave)” filter sets.  Using the XRT, ground-base observations, calculated global magnetic field and numerical simulation, we can progress the study of the flare-associated waves.

  32. END Thank you very much for your attention.

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